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  1. OpenShift Virtualization
  2. CNV-21186

[2125985] Unable to start windows VMs on PSI setups

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    • Urgent

      +++ This bug was initially created as a clone of Bug #2119069 +++

      +++ This bug was initially created as a clone of Bug #2115371 +++

      Description of problem:
      Unable to start Windows VMs on PSI setups.

      Version-Release number of selected component (if applicable):
      4.11.0-587

      How reproducible:
      On PSI Setups.

      Steps to Reproduce:
      1. Create any windows VMs on PSI Setups
      2.
      3.

      Actual results:
      Windows VMs on PSI Setups, fail to start with the below message.

      {"component":"virt-controller","level":"info","msg":"reenqueuing VirtualMachineInstance default/vm-win10-411new","pos":"vmi.go:272","reason":"failed to determine the lowest tsc frequency on the cluster: no schedulable node exposes a tsc-frequency","timestamp":"2022-08-04T11:48:10.942248Z"}

      As we don't see any tsc frequency label on worker nodes of PSI Clusters.

      Expected results:
      Windows VMs on PSI Setups work fine.

      Additional info:

      — Additional comment from Kedar Bidarkar on 2022-08-08 14:17:27 UTC —

      Moving this to 4.11.1 till we have a solution, where in we are not required to skip these tests in PSI Setups.

      — Additional comment from Kedar Bidarkar on 2022-08-08 16:11:49 UTC —

      This issue is seen because the tsc labels are not present on the PSI Clusters ( Virtual Machine based worker nodes) Worker Nodes.
      cpu-timer.node.kubevirt.io/tsc-frequency=2095077000
      cpu-timer.node.kubevirt.io/tsc-scalable=true

      — Additional comment from on 2022-08-17 12:40:12 UTC —

      This is to track that the fix for this lands in the latest release as well as z stream.

      — Additional comment from Marcelo Tosatti on 2022-08-24 14:35:22 UTC —

      Intel documentation states:

      17.12.1 Invariant TSC
      The time stamp counter in newer processors may support an enhancement, referred
      to as invariant TSC. Processors support for invariant TSC is indicated by
      CPUID.80000007H:EDX[8].
      The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is
      the architectural behavior moving forward. On processors with invariant TSC
      support, the OS may use the TSC for wall clock timer services (instead of ACPI or
      HPET timers). TSC reads are much more efficient and do not incur the overhead
      associated with a ring transition or access to a platform resource.

      -------

      Lets consider what needs to be done regarding tsc and VM migration:

      1) Invariant TSC (invtsc flag) should only be exposed to a VM if the host
      it runs on has Invariant TSC (check /proc/cpuinfo output for "invtsc").

      2) Migration of a VM that has invariant TSC flag enabled should be
      performed to:

      -> A destination host that has invariant TSC.
      -> A destination host that is able to execute a guest with
      TSC frequency of the source host (which is either
      a destination host with the same frequency as the source
      host, or a destination host with TSC scaling available).

            sgott@redhat.com Stuart Gott
            iholder@redhat.com Itamar Holder
            Kedar Bidarkar Kedar Bidarkar
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              Created:
              Updated:
              Resolved: